So you can imagine how I felt when, on that mapping trip I took, I stumbled on a mountain of the peculiarly greenish rock that is characteristic of the jovium deposits on Jupiter.

"I immediately staked the claim, then worked back through the jungle to where, about twenty miles away, I had left the Wanderer. I had to get a badinite flash, you see, to take a sample in, according to the rules of the B. P. C. Mineral Claims Commission. The stuff was almost pure. I got a nasty burn on my arm when I brushed against it, too.

"Well—you know what jovium is used for. It's the catalyst that made interplanetary voyaging practical. Oh, we had space ships before the deposits were found on Jupiter. But they had to carry such enormous volumes of fuel to get anywhere that there was neither space nor carrying capacity left for commercially practicable freight nor, what is more important, in the present instance, heavy armament...

"The discovery of jovium initiated the commercial exploitation of the far planets. It initiated also a race in spatial armament between Mars and Earth, that so far has been a dead heat."

Single-fueled rockets, also called monopropellant rockets, actually exist. The most commonly used monopropellant is hydrazine (N2H4), a chemical which is a strong reducing agent. The most common catalyst is granular alumina coated with iridium.

Compare to the materials used in Bussard ramjets from Larry Niven's 1976 novella World out of Time and protonite from Jack Williamson's 1931 story Twelve Hours to Live.